Trace Elements In Sediments Research Articles

Environmental health risks of trace elements in sediment using multivariate approaches and contamination indices

Environmental health risks of trace elements in sediment using multivariate approaches and contamination indices

Assessment of Amphibola crenata as a bioindicator of estuarine trace element pollution using biochemical and physiological endpoints

To assess its utility as a bioindicator of estuarine contamination, Amphibola crenata, a pulmonate mud snail, was collected from 17 estuaries in New Zealand. Whole-body soft tissue trace element concentrations were measured via quadrupole inductively coupled plasma mass spectrophotometer (Q-ICP-MS) and were found to be significantly positively correlated with sediment trace element profiles for arsenic, copper and lead. Snails from polluted estuaries generally displayed higher ammonia excretion rates, elevated whole-body soft tissue catalase activity and lipid peroxidation compared to snails from reference sites. Across all sites haemolymph glucose was positively correlated with the tissue burdens of arsenic, copper, nickel and zinc, while haemolymph protein was negatively correlated with arsenic, cadmium and zinc soft tissue concentrations, indicative of altered energy metabolism associated with trace element contamination. Overall, sites were distinguishable by application of the array of measures employed. Our findings suggest that gastropods have significant value as bioindicators of estuarine health.

Impact of Soluble and Exchangeable Concentrations of Elements in Surface Sediments from Recreational Areas on Culturable Bacterial Behaviors

Contamination of major and trace elements in sediments is a global concern due to their potential risks to organisms. Bacteria also play vital roles in ecosystem processes and human health. However, the environmental adaptation of bacterial species due to human activities remains unclear. Therefore, in this study, surface sediments were collected from 12 recreational areas in Istanbul, Türkiye. Major and trace elements were determined in soluble and exchangeable fractions of sediments using inductively coupled plasma–optical emission spectrometry (ICP-OES). In addition, viability and primary biochemical and oxidative markers (protein, antioxidant, and lipid peroxidase) of gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa were assessed with exposure to soluble and exchangeable fractions of sediments from 1 to 42 h. The results showed that Na, Mg, K, Ca, P, Fe, Cu, Mn, Zn, and Al were present at average concentrations of 1254.1 ± 574.5, 234857.0 ± 126335.7, 109960.3 ± 73248.6, 201343.0 ± 84426.4, 124.0 ± 77.1, 129.5 ± 82.4, 36.0 ± 22.8, 25.2 ± 32.8, 26.3 ± 16.4, and 186.5 ± 76.7 mg/kg, respectively. The bacterial responses to the soluble and exchangeable fractions of sediments showed that approximately 27% of Staphylococcus aureus exhibited inhibition at short exposures; the inhibition levels were 14% to 34% for Pseudomonas aeruginosa. However, the inhibition decreased and no specific viability changes were observed at longer exposures compared to controls. The viability of bacteria is explained by the protein, antioxidant and lipid peroxidation with moderate and strong correlations. The bacterial responses were evaluated using elemental concentrations, and adaptation was explained by the correlation results.

Assessment of trace and macroelement accumulation in cyprinid juveniles as bioindicators of aquatic pollution: effects of diets and habitat preferences

Juveniles of three cyprinids with various diets and habitat preferences were collected from the Szamos River (Hungary) during a period of pollution in November 2013: the herbivorous, benthic nase (Chondrostoma nasus), the benthivorous, benthic barbel (Barbus barbus), and the omnivorous, pelagic chub (Squalius cephalus). Our study aimed to assess the accumulation of these elements across species with varying diets and habitat preferences, as well as their potential role in biomonitoring efforts. The Ca, K, Mg, Na, Cd, Cr, Cu, Fe, Mn, Pb, Sr, and Zn concentration was analyzed in muscle, gills, and liver using MP-AES. The muscle and gill concentrations of Cr, Cu, Fe, and Zn increased with trophic level. At the same time, several differences were found among the trace element patterns related to habitat preferences. The trace elements, including Cd, Pb, and Zn, which exceeded threshold concentrations in the water, exhibited higher accumulations mainly in the muscle and gills of the pelagic chub. Furthermore, the elevated concentrations of trace elements in sediments (Cr, Cu, Mn) demonstrated higher accumulation in the benthic nase and barbel. Our findings show habitat preference as a key factor in juvenile bioindicator capability, advocating for the simultaneous use of pelagic and benthic juveniles to assess water and sediment pollution status.

Wide Riparian Zones Inhibited Trace Element Loss in Mining Wastelands by Reducing Surface Runoff and Trace Elements in Sediment.

The diffusion of trace elements in mining wastelands has attracted widespread attention in recent years. Vegetation restoration is an effective measure for controlling the surface migration of trace elements. However, there is no field evidence of the effective riparian zone width in mining wastelands. Three widths (5 m, 7.5 m, and 10 m) of Rhododendron simsii/Lolium perenne L. riparian zones were constructed in lead-zinc mining wastelands to investigate the loss of soil, cadmium (Cd), copper (Cu), arsenic (As), lead (Pb), and zinc (Zn). Asbestos tiles were used to cut off connections between adjacent plots to avoid hydrological interference. Plastic pipes and containers were used to collect runoff water. Results showed that more than 90% of trace elements were lost in sediment during low coverage and heavy rainfall periods. Compared with the 5 m riparian zone, the total trace element loss was reduced by 69-85% during the whole observation period in the 10 m riparian zone and by 86-99% during heavy rain periods in the 10 m riparian zone, which was due to reduction in runoff and concentrations of sediment and trace elements in the 10 m riparian zone. Indirect negative effects of riparian zone width on trace element loss through runoff and sediment concentration were found. These results indicated that the wide riparian zone promoted water infiltration, filtered soil particles, and reduced soil erosion and trace element loss. Riparian zones can be used as environmental management measures after mining areas are closed to reduce the spread of environmental risks in mining wastelands, although the long-term effects remain to be determined.

Trace element geochemistry of sediments in the Pearl River Estuary and its implication for provenance

The Pearl River system is China’s third longest river and the Pearl River Estuary is a major estuary in China. In the paper, a sediment core collected from the coastal zone in the Pearl River Estuary was analyzed for trace element concentrations and grain size to identify provenance during the past decades. In addition, the tectonic framework of the study area has also been studied using reliable geochemical tracers, including rare earth elements (REEs) and trace elements. The results reveal a significant contribution of reworked sediment from multiple sources. Discrimination diagrams suggest that the sediments display felsic characteristics with recycled components, and therefore, the source rock types of the sediments are presumed to be granitic rocks. The REE patterns observed in the samples primarily reflect the influence of an ancient continental crust that contains felsic materials on the sediments with an LREE/HREE ratio of 7.94–9.56 (mean 8.46) and a δ Eu value of 0.61–0.70 (mean 0.65). The sediments are plotted into a zone of continental island arcs, which was formed during the late Mesozoic subduction of the ancient Pacific. The study on the source of sediment cores shows that the main source of sediments in this area excludes the possibility of the upper middle river from the Pearl River Watered, which reflects the importance of the lower Pearl River Basin, especially the Dongjiang River, for material transport in the study area. Our results demonstrate that the geochemical characteristics of trace elements in sediment could provide an efficient approach to identify sediment provenance in estuaries worldwide.

Evaluation of trace elements concentration using sediments and mussels as bioindicators and pollution indices in the Egyptian Red Sea

The current work was designed to evaluate the pollution status of the coastline region of the Egyptian Red Sea through monitoring the trace elements in sediments and mussels (Brachidontes variabilis and Modiolus auriculatus) that sampled during winter and summer 2019 from nineteen stations along the investigated area. The analyzed elements showed an annual mean of 20.21, 2.08, 4.79, 46.41, 11.35, 18.14, 128.93 and 12,520.07 μg/g (sediments), 1.02, 0.39, 3.35, 23.73, 0.59, 1.14, 1.43 and 81.94 μg/g (B. variabilis) and 1.39, 0.47, 1.70, 24.69, 0.77, 1.66, 2.16 and 119.80 μg/g (M. auriculatus) for Pb, Cd, Cu, Zn, Co, Ni, Mn and Fe, respectively. The summer recorded highest values of all studied elements in the mussels' species with significant temporal variations (p < 0.05) for the most investigated elements. The pollution indices like CF, PLI, MPI, Igeo and EF were calculated to evaluate the elements contamination degree in the examined areas.

Distinctive Accumulation Patterns of Trace Elements in Sediments of Bedrock Rivers (Miño River, NW Iberian Peninsula)

Sediment compositions and enrichment patterns are investigated in an urban reach of a bedrock river, the Miño River passing through Ourense City, Spain. This study focuses on the trace element distribution in different fractions to gain insights into trace element enrichment. To assess enrichment, a context-specific approach was employed, based on the mean, the standard deviation of the estimated background, and the empirical rule, avoiding the pitfalls of general and arbitrary thresholds. Notably, the &lt;0.063 mm and &lt;2 mm fractions showed differential accumulation patterns. Both fractions serve to detect enrichments that can be indicative of contamination, but they measure different things, the maturity of sediments and postdepositional processes being key factors in understanding the sediment composition and enrichments. These findings also highlight the role of rock cavities, particularly those hosting permanent deposits, as traps for trace elements and their potential significance in assessing environmental enrichment. This work contributes to understanding sediment compositions and enrichment dynamics in bedrock rivers. It also underscores the significance of considering site-specific approaches for enrichment assessment and the necessity for further research to unravel the mechanisms driving differential accumulation within distinct depositional environments.

Evaluation of trace elements in the sediments of intertidal zone around Mahin-Ugbo Area, southwestern Nigeria

This study assessed the spatial distribution of Trace Elements (TE) in the muddy sediments of the Mahin-Ugbo coastal area of Southwestern Nigeria, using Inductively Coupled Plasma-mass spectrometry, (ICP-MS). The physicochemical parameters (pH, EC and TDS) of the sediments were also determined. Results showed that the mean values for pH, E.C and TDS were 5.09, 153.6 μs/cm and 76.8 mg/L, respectively. Further, there was a varying distribution pattern of TE concentrations: Mn&gt; Zn &gt; Ba &gt; Cr &gt; V &gt; Sr &gt; Pb &gt; La &gt; Cu &gt; Ni &gt; Co &gt; As &gt; Th &gt; Sc &gt; Ga. The As, Pb, and Zn concentrations in the sediment with mean values of 11.2, 40.4 and 122.1 ppm, respectively, were significantly higher than the average concentrations of As (10 ppm), Pb (20 ppm) and Zn (90 ppm) in natural shale, suggesting anthropogenic TE enrichment in the study area. To corroborate this, the TE source apportionments in the sediments using correlation coefficient, bi-variant plots and principal component analyses showed that the TE enrichment may have been anthropogenically induced. Pollution status assessments using I-geo, contamination factors and pollution load index indicated that the study area's sediments is slightly to moderately polluted. These findings suggest that although the area is not heavily polluted, increasing human activities, from inland rivers to the coastal area, in the study area will in no time be a cause for concern.

The contamination appraisal and depthwise scrutiny of trace elements in sediments of the Moyur river, Bangladesh

Trace element pollution in river sediments from multiple sources can pose ecological risks to aquatic systems. Therefore, the evaluation of elemental contamination and ecological risks in sediments is important for the proper management of a river system. In this study, concentrations of 12 major and trace elements (Cr, Mn, Fe, Al, Br, Rb, V, Co, As, Ta, Th, and U) were measured in sediments of the Moyur River, Bangladesh using neutron activation analysis technique. It is observed that concentrations of As, Br, Rb, Ta, Th, and U are higher than those of the upper continental crustal average values. Different environmental contamination indicators suggest that Moyur River sediments are heavily contaminated by Br. The pollution load index derived from the contamination factor also indicate the deteriorating condition of the sediments at different sampling points of the river. The depth-wise variation of the trace elements elucidates their contamination profiles along the sediment cores. An ecological risk assessment by different ecological risk factors and sediment quality guidelines indicates that sediments of the Moyur River are subjected to ecological risk by Cr and As. The multivariate statistical analyses indicate the origin and transport behavior of the studied elements in the sediments of the river. This study will provide baseline elemental concentration data for future monitoring of the contamination and to develop effective pollution control strategies for this urban river.

Seasonal and spatial contamination of trace elements in sediments and fish tissues (Mugil Chephalus) from Annaba gulf (North East of Algeria)

This research is devoted to assessing the pollution within a Mediterranean Sea area in the East coast of Algeria, which is known for its port and industrial activities. This study aims to assess the health status of the Gulf of Annaba located in the extreme North-East of Algeria by examining the contamination level by trace elements (Cu, Zn, Pb, Cd, Hg) in the sediments and muscles of Mugil cephalus fish. The obtained results manifest significant variations in metal levels in the sediments throughout the stations and the sampling seasons. The contamination by (Zn, Cu, Pb, Cd) of Joannonville and Sidi Salem stations is observed during both seasons whereas at the Chapuis station occurs only during the summer. The contamination indices are higher than 3, hence classifying the sediments of these three stations as “sediments at risk”. Joannonville station manifests high levels of Hg only during the summer. For the muscles of M. cephalus, the contamination levels are found to be dependent on the species and the studied station. The fish inhabiting Joannonville and Sidi Salem show higher levels of (Zn, Pb, Cd) compared to the FAO/WHO standards, whereas the Pb level at Chapuis exceeds the standard during summer. Accordingly, the consumption of fish from Joannonville, Sidi Salem and Chapuis stations presents a serious threat regarding the toxicological risks based on the observed levels of contamination.

Trace Elements in Sediment and Urban Water Samples: an Assessment of Metal Pollution

In this study, trace elements (Cd, Cr, Cu, Pb and Zn) concentrations were determined by flame atomic absorption spectrometry (FAAS) in environmental compartments (water and superficial sediments) near places of vehicle use and maintenance, aiming to investigate if in these places the trace elements had high concentrations. The content of trace elements found on the samples was compared to the maximum values recommended by resolutions of CONAMA (Conselho Nacional do Meio Ambiente) n. 357 from 2005 for water and n. 454 from 2012 for sediments. Points 11 and 13 were the most critical, with concentrations higher than the recommended for the elements Cu and Pb, either for water or sediment samples. Geoaccumulation index (Igeo) for Cd and Cr in the sediment samples indicated high to extreme contamination in points 5 and 13, while the other elements indicated moderated contamination.

Corrigendum: Water Sci Technol 1 November 2021; 84 (9): 2578-2590: Contamination and ecological risk assessment of trace elements in sediments of the Anzali Wetland, Northern Iran, Marjan Esmaeilzadeh, Elham Mahmodpor, Somayeh Haghighat, Sara Esmaeilzadeh, Hamide Aliani, Najmeh Yazdanfar, https://dx.doi.org/10.2166/wst.2021.455.

Corrigendum: Water Sci Technol 1 November 2021; 84 (9): 2578-2590: Contamination and ecological risk assessment of trace elements in sediments of the Anzali Wetland, Northern Iran, Marjan Esmaeilzadeh, Elham Mahmodpor, Somayeh Haghighat, Sara Esmaeilzadeh, Hamide Aliani, Najmeh Yazdanfar, https://dx.doi.org/10.2166/wst.2021.455.

Trace elements in sediments and plankton from two high-altitude lakes in a volcanic area from North Patagonia, Argentina.

This study analyzes the distribution of nine potentially toxic trace elements (arsenic, antimony, bromine, cobalt, chromium, mercury, rubidium, selenium, and zinc) in sediments and plankton from two small mesotrophic lakes in a non-industrialized area impacted by the Caviahue-Copahue volcanic complex (CCVC). The two lakes have different plankton community structures and received different amounts of pyroclastic material after the last CCVC eruption. Trace element concentrations of surface sediments differed between lakes, according to the composition of the volcanic ashes deposited in the lakes. The size of organisms was the principal factor influencing the accumulation of most trace elements in plankton within each lake, being trace element concentrations generally higher in the microplankton than in the mesozooplankton. The planktonic biomass in the shallower lake was dominated by small algae and copepods, while mixotrophic ciliates and different-sized cladocerans dominated the deeper lake. These differences in the community structure and species composition influenced the trace element bioaccumulation, especially in microplankton, while habitat use and feeding strategies seem more relevant in mesozooplankton bioaccumulation. This work contributes to the scarce records of trace elements and their dynamics in plankton from freshwater ecosystems impacted by volcanic activity.

Lake-wide assessment of trace elements in surface sediments and water of Lake Sevan

Lake Sevan (Armenia) is one of the large freshwater high-mountain lakes of Eurasia. Detailed information about the extent and fate of trace elements on lake sediment and water quality has not been published yet. For this reason, surface sediment and water samples were collected from the southern and northern basins of Lake Sevan to determine trace element concentrations and assess the trace element behaviour. Geo-accumulation index, potential ecological risk index, and hazard index were calculated to estimate the environmental risk potential. In comparison to reference values, the investigated sediment samples contained elevated concentrations frequently for V, Cr, Co, Ni, Mo, Cd, Be, Ti, Rb, Sr, Se, Hf, and Th and occasionally for Cu, As, Li, B, Ag, Sb, Tl, Bi, U, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Tm. An overall potential ecological risk posed by all the investigated trace elements in the sediments was assessed to be moderate-considerable, however, Mo, Hg, and Cd were the elements with the highest ecological risk potential. The two basins of the lake showed significantly different behaviour according to the investigated trace element contents in the sediments to be higher in the bigger basin compared to the smaller basin. In comparison to reference concentrations in water samples according to the use of the adapted geo-accumulation index, elevated values for Ti, Cr, Cu, Cd, and Pb were observed. Elevated concentration was also observed in the case of B in nearly all water samples in comparison with literature values. Nevertheless, several water samples can be seen as not strongly anthropogenic influenced by Co, Ni, Sn, Sb, Ag, Hg, and Bi. The concentrations of trace elements in the lake water caused health risks to humans particularly children in the case of lake water used for drinking purposes, moreover, As was the main element posing health hazards. The results point out further attention to the sources of elevated trace elements in Lake Sevan, including anthropogenic influences and geological characteristics.

Uranium as reference element to estimate the background of “Anthropocene” sensitive trace elements in sediments of the land-ocean continuum (Ulla-Arousa, NW Iberian Atlantic Margin)

Determining the background is a crucial step in differentiating between natural and anthropogenic components in environmental samples. Geochemical normalization is a standard procedure for determining the background contents of trace elements in sediment samples, which involves the careful selection of a reference element. Aluminum (Al), iron (Fe), and other major, minor, and even trace constituents of sediments are commonly used as reference elements. A suitable reference element should behave conservatively, with contents that are not significantly affected by anthropogenic factors or post-depositional processes.In this study, the performance of uranium as a reference element in sediment samples taken from the Ulla River was tested. The Ulla River drains a mainly granitic basin in the Iberian Atlantic Margin, and samples were collected from headwaters to the coastal area. Iterative least squares simple regression was used to estimate the background contents (as background functions) of six trace elements of environmental concern, including arsenic (As), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn).Uranium demonstrated satisfactory performance with correlation coefficients ranging from approximately 0.7 for Cu to 0.9 for As. The background-estimated contents of the six target elements were in good agreement with several references at different geographical scales, with differences possibly attributed to peculiarities in the local lithology. Thus, uranium can be considered a suitable normalizing element. However, it was tested in a relatively homogenous granitic basin and, like any other reference element, should not be used automatically without empirical corroboration.

Effects of trace elements on benthic macroinvertebrate distribution in the sediments of two rivers in the Olifants River Basin, South Africa

Many freshwater ecosystems are facing ecological challenges such as influx of trace elements from human activities, and sediments behave as a sink for trace elements in these environments. Trace element contamination in river sediments is a major environmental concern due to its devastating effect on benthic organisms. The aim of this study was to assess the effect of trace elements in sediments on the distribution of benthic macroinvertebrates in the Blyde and Mohlapitsi rivers of the Olifants River Basin, South Africa. Sediment samples and benthic macroinvertebrates were collected from six sites along each river. The results showed variations in the concentration of the trace elements in the sediment and the distribution of benthic macroinvertebrates among the different sites and between the two rivers. Both rivers recorded high taxa richness and sensitive taxa were well represented in most parts of the rivers, an indication that the rivers are not highly disturbed. There were insignificant correlations between most of the trace elements and the abundance of the benthic macroinvertebrates, though some taxa showed significant correlations with the trace elements. Despite the low impact of the trace elements on the distribution and diversity of benthic macroinvertebrates, ecological health of the rivers and structural distribution of macroinvertebrates may be affected in the future due to increasing human activities in the catchments. It is therefore recommended that effluents from human activities should be controlled to prevent a further degradation of the rivers to protect macroinvertebrates and other aquatic biota.

Trace elements in surface sediments from Xinyanggang River of Jiangsu Province, China: Spatial distribution, risk assessment and source appointment

The Xinyanggang River in Yancheng City, one of the essential rivers entering the Yellow sea, has imported abundant pollutants to the coast of Jiangsu Province. Trace elements (Cr, Ni, Cu, Zn, As, Rb, Sr, Mo, Pb, Th, U, Sc, Ga, Se, Zr, Nb, and Sn) in surface sediments in the Xinyanggang River were measured to analyze the spatial distribution, risk assessment, and source appointment. The results showed that the parts of 17 trace elements presented high average values in river sediments, such as Zr (309.19 mg/kg), Sr (182.72 mg/kg), Zn (77.67 mg/kg), and Cr (70.63 mg/kg). Compared with some coastal rivers, the Xinyanggang River was polluted by certain trace elements, such as Cr, Zn, and As. Based on the analysis of the enrichment factor (EF), the contamination factor (CF), the pollution load index (PLI), and the geoaccumulation index (Igeo), trace elements in sediments showed unpolluted to moderate contamination and mild to moderate enrichment. Among them, Zn, Pb, and Sn were highly polluted. The multivariate analysis, the principal component analysis-multiple linear regression (APCS-MLR) model, and the Unmix model identified four contributing trace element sources. Cr, Th, U, Se, Zr, and Nb originated from manufacturing industries and hydrodynamic transport erosion. Ni, Rb, Sc, and Ga were attributed to natural source. Cu, Zn, Mo, Pb, and Sn were contributed from mixed sources including industrial wastewater and transportation emissions. As and Sr were associated mainly with mixed sources of agriculture and combustion. These four sources of metals accounted for 22.5 %, 5.7 %, 15.3 %, and 11.1 % by using the APCS-MLR model, whereas 22.9 %, 39.7 %, 17.5 %, and 19.9 % by using the Unmix model, respectively.

Trace Elements in Sediments of Two Lakes in the Valley of the Middle Courses of the Ob River (Western Siberia)

Lake sediments accumulate various pollutants and act as efficient natural archives suitable for reconstruction the environmental conditions of the past. In contrast to fairly good knowledge of mineral sediments in lakes of European and North America boreal lakes, Siberian lakes of the boreal zone remain quite poorly studied. In this work, two cores of lake sediments of the Ob River valley were investigated. Elemental analyses were carried out on the sediments, losses on ignition were determined, and the rate of sedimentation was measured from the activity of Pb-210 and Cs-137. According to the content of organic matter, bottom sediments belong to different types: clastic (Lake Inkino, located in the Ob River floodplain) and organogenic (Lake Shchuchie on the second terrace). The rate of sedimentation in Lake Shchuchie is several times higher than that in Lake Inkino. The sediments of Lake Inkino are similar in composition (including the pattern of rare earth elements) to the suspended particulate matter of the Ob River as well as to average detrital matter of the upper continental crust. Sediments of Lake Shchuchie (sapropels) are enriched in a number of heavy metals. Based on the elemental composition, signs of diagenetic processes and authigenic mineral formation were determined, such as accumulation of carbonates and the formation of manganese oxides and hydroxides. There is an enhanced recent input of Cr, Co, Cu, Zn, Cd, Sb, Pb, and Bi in the upper layers of sediments as a result of atmospheric anthropogenic pollutant deposition.

Mobile trace elements in sediments from lakes Hawassa, Koka, and Ziway in the Ethiopian Rift Valley.

The present work focuses on total concentrations of trace elements such as chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), and lead (Pb) and their operationally defined speciation in surface sediments from three Ethiopian Rift Valley Lakes (Hawassa, Koka, and Ziway). Total concentrations were determined using inductively coupled plasma-mass spectrometer (ICP-MS). A six-step sequential extraction was also applied to evaluate the mobilization potential of these elements. Compared with the consensus-based sediment quality guidelines (SQGs) developed for freshwater ecosystems, the total Zn concentration in sediments from Lakes Hawassa and Ziway, as well as Cr, Ni, and Zn in sediments from Lake Koka, was higher than the probable effect concentration (PEC), suggesting that these elements could have a negative effect on benthic organisms. The sequential extraction results showed that Cd, Mn, and Se were to a certain extent associated with the reversible fractions (F1-F3) in sediments, and thereby more mobile than the other investigated trace elements. Predictions of mobility of trace elements using the distribution coefficients (Kd) values were also in agreement with the sequential extraction results. Furthermore, multivariate statistical analyses showed that redox-sensitive fractions (F4 and F6) and the residual fraction (F7) were the dominant factors controlling most trace element mobility. Finally, applying the Risk Assessment Code (RAC) classification system, results showed that Mn in Lake Koka could pose a high risk, while Cd and Mn in Lake Hawassa as well as Cd, Mn, and Se in Lake Ziway sediments could pose medium risk to benthic organisms.